Slime control compositions and their use

ABSTRACT

The present invention relates to certain processes and composition useful for inhibiting the growth of slime in water and, in particular, water used for industrial purposes, for example, in the manufacture of pulp paper, in the manufacture of paper, in cooling water systems and in effluent water treatment. The novel processes and compositions of the present invention are processes or mixtures which show unexpected synergistic activity against microorganisms, including bacteria, fungi and algae, which produce slime in aqueous systems or bodies which are objectionable from either an operational or aesthetic point of view. Specifically the invention is directed to the use of compositions comprising a combination of N-2-nitrobutyl morpholine and pentachlorophenol.

United States Patent 1191 Shema et al.

1111 3,860,517 [451 Jan, 14,1975

SLlME CONTROL COMPOSITIONS AND THEIR USE Inventors: Bernard F. Shema, Glenside; Robert H. Brink, Jr., Doylestown, both of Assignee: Betz Laboratories, Inc., Trevose, Pa.

Filed: June 15, 1973 Appl. No.: 370,484

Bollenback 424/347 3,054,749 9/1962 Bennett et a1. 424/248 X Primary Examiner-Thomas G. Wyse Attorney, Agent, or Firm-Alexander D. Ricci [5 7] ABSTRACT The present invention relates to certain processes and composition useful for inhibiting the growth of slime in water and, in particular, water used for industrial purposes, for example, in the manufacture of pulp paper, in the manufacture of paper, in cooling water systems and in effluent water treatment, The novel processes and compositions of the present invention are processes or mixtures which show unexpected synergistic activity against microorganisms, including bacteria, fungi and algae, which produce slime in aqueous systems or bodies-which are objectionable from either an operational or aesthetic point of viewv Specifically the invention is directed to the use of compositions comprising a combination of N-2-nitrobutyl morpholine and pentachlorophenol.

8 Claims, N0 Drawings SLIME CONTROL COMPOSITIONS AND THEIR USE BACKGROUND OF THE INVENTION The formation of slime by microorganism is a problem which attends many systems. For example, lagoons, lakes, ponds, pools and such systems as cooling water systems and pulp and paper mill systems all possess conditions which are conducive to the growth and reproduction of a slime-forming microorganisms. In both once-through and recirculating cooling systems, for example, which employ large quanities of water as a cooling medium, the formation of slime by microorganisms is an extensive and constant problem.

Airborne organisms are readily entrained in the water from cooling towers and find this warm medium an ideal environment for growth and multiplication. Aerobic and heliotropic organisms flourish on the tower proper while other organisms colonize and grow in such areas as the tower sump and the piping and passages of the cooling system. Such slime serves to deteriorate the tower structure in the case of wooden towers. In addition, the deposition of slime on metal surfaces promotes corrosion. Furthermore, slime carried through the cooling system plugs and fouls lines, valves strainers, etc. and deposits on heat exchange surfaces. In the latter case, the impedance of heat transfer can greatly reduce the efficiency of the cooling system.

In pulp and paper mill systems, slime formed by microorganisms is also frequently and, in fact, commonly encountered. Fouling or plugging by slime also occurs in the case of pulp and paper mill systems. Ofgreater significance, the slime becomes entrained in the paper produced to cause breakouts on the paper machines with consequent work stoppages and the loss of production time or unsightly blemishes in the final product which results in rejects and wasted output. The previously discussed problems have resulted in the extensive utilization of biocides in cooling water and pulp and paper mill systems. Materials which have enjoyed widespread use in such applications include chlorine organo-mercurials, chlorinated phenols, organobromines, and various organo-sulfur compounds. All of these compounds are generally useful for this purpose but each is attended by a variety of impediments. For example, chlorination is limited both by its specific toxicity for slime-forming organisms at economic levels and by the ability of chlorine to react which results in the expenditure of the chloring before its full biocidal function may be achieved. Other biocides are attended by odor problems and hazards in respect to storage, use or handling which limit their utility. To date, no one compound or type of compound has achieved a clearly established predominance in respect to the applications discussed. Likewise, lagoons, ponds, lakes, and even pools, either used for pleasure purposes or used for industrial purposes for the disposal and storage of industrial wastes, become, during the warm weather, besieged by slime due to microorganism growth and reproduction. In the case of the recreational areas, the problem of infection, etc. is obvious. In the caseof industrial storage or disposal of industrial materials, the microorganisms cause additional problems which must be eliminated prior to the materials use or the waste is treated for disposal.

Naturally, economy is a major consideration in respect to all of these biocides. Such economic considertreated. To date, none of the commercially available biocides have exhibited a prolonged biocidal effect. Instead, their effectiveness is rapidly reduced as the result of exposure to physical conditions such as temperature, association with ingredients contained by the system toward which they exhibit an affinity or substantivity, etc., with a resultant restriction or elimination of their biocidal effectiveness.

As a consequence, the use of such biocides involves their continuous or frequent addition to systems to be treated and their addition to aplurality of points or zones in the systems to be treated. Accordingly, the cost of the biocide and the labor cost of such means of applying it are considerable. In other instances, the difficulty of access to the zone in which slime formation is experienced precludes the effective use of a biocide. For example, in a particular system there is no access to an area at which slirne formation occurs and it may only be applied at a point which is upstream in the flow system. However, the physical or chemical condition, e.g. chemical reactivity, thermal degradation, 1 etc. which exist between the point at which the biocide may be added to the system and the point at which its biocidal effect is desired render the effective use of a biocide impossible.

Similarly, in a system experiencing relatively slow flow, such as a paper mill, if a biocide is added at the beginning of the system, its biocidal effect may be completely dissipated before it has reached all of the points at which this effect is desired or required. As a consequence, the biocide must be added at a plurality of points, and even then a graduated biocidal effect will be experienced between one point of addition to the system and the next point downstream at which the biocides may be added. In addition to the increased cost of utilizing and maintaining plural feed points, gross ineconomies in respect to the cost of the biocide are experienced. Specifically, ateach point of addition, an excess of the biocide is added to the system in order to compensate for that portion of the biocide which will be expended in reacting with other constituents present in the system or experiencephysical changes which impair its biocidal activity.

It is an object of the present invention to provide methods and compositions for controlling slimeforming microorganisms in aqueous systems such as cooling water systems and pulp and paper mill systems, and for controlling slime formation or microorganism populations in aqueous bodies in general. Moreover, another object of the invention is the provision of methods and compositions for controlling slime forming microorganisms in any aqueous system which is conducive to the growth and reproduction of microorganism and, in particular, cooling water and paper and pulp mill systems which emplou a combination of N-2-nitrobutyl-morpholine and Pentachlorophenol.

In practice of the'inventio'n, the combination is added to the particular system being treated for example, cooling water systems, paper and pulp mill systems, pools, ponds, lagoons, lakes, etc. in a quantity adequate to control the slime-forming microorganisms which are Q, Quantity of Compound A, in the mixture, producing an end point Q, Quantity of Compound B, in the mixture, producing an end point For mixtures of Compounds A and B, and for Compound A and Compound B acting alone, the following results were observed. Summary of, synergistic activity of varying percentages of Compound A and Compound B: SYNERGISTIC COMBINATION Compound A: N2-nitrobutyl morpholine Compound B: Pentachlorophenol TABLE I TEST ORGANISM AEROBACTER AEROGENES Q O O Q Weight ratio Quantities Producing End Points (ppm) A B Y A B of A m B Q Q Mixture Q Q Q Q A B Mixture a b a b about 5:95 to about 95:5. When these two ingredients are mixed, the resulting mixtures possess a high degree of slimicidal activity which could not have been predegree of the biocidal effectiveness which is provided by each of the ingredients may be exploited without use of the higher concentrations of each.

To demonstrate the synergism which is provided by the inventive combinations of compounds, the data as set forth in the Table below was developed.

EXAMPLE 1 Synergism was demonstrated by adding Compound A and Compound B in varying ratios and over a range of concentrations to liquid nutrient agar medium (Tryptone Glucose Extract Agar) at approximately C. After the medium had solidified in Petri plates, it was inoculated with a bacterial suspension. Following two days incubation, the lowest concentration of each ratio which prevented growth on the agar medium was taken as the end point. End points for the various mixtures were then compared with end points for the pure active ingredients working alone in concomitantly prepared agar medium plates. Synergism was determined by the method described by F. C. 'Kull, P. C. Eisman, H. D. Sylwestrowicz and R. L. Mayer, APPLIED MICROBI- OLOGY, 9, 538-41, (1946), and the relationships,

(QA/Q (Qll/Qb) (l is synergism,) l is antagonism,

erence can be made to U.S. Pat. No. 3,231,509 and-its file history where data of this nature was consideredto be acceptable. Moreover, the article'by Kull et al. published in APPLIED MICROBIOLOGY, 9, 538-54'1, will furnish additional information in this regard.

For the testing to ascertain synergistic Behavior, Aerobacter aerogenes was favored since this microorganism is found to exist and found to be most troublesome in pulp and paper productingprocesses, as well as in cooling towers. Moreover, the microorganism is difficult to control and/or kill and accordingly its existence does give rise to troublesome slime. In view of the foregoing, it can then be appreciated that since Aerobacter aerogenes is prevalent in most slime-affected systems and since this microorganism is difficult to control or kill, that once control of this microorganism is maintained, then for all practical purposes the total microorganism population with its different types is considered controlled.

When the inventive compositions are employed in the treatment of cooling or paper mill water, they are preferably utilized in the form of relatively dilute solutions or dispersions. For example, a preferred solution comprises between 5% to 65% by weight of thesynergistic combination in admixture with various solvents and solubilizing agents.

Surfactants such as the alkylaryl polyether alcohols, polyether alcohols, alkyl benzene sulfonates and sulfates, and the like, may also be employed to enhance the dispersibility and stability of these formulations. The foregoing solution of the biocidal compositions are utilized in order to insure the rapid and uniform dis persibility of the biocides within the industrial water which is treated. It has been found that either aqueous or non-aqueous solvents are generally suitable-in the preparation of compositions of the invention. For example, organic solvents such as methyl cellosolve and aliphatic and aromatic hydrocarbons, e.g., kerosene, can be used quite successfully. Based upon the synergism study as outlined above, it was ascertained that in their ability to formslime in actual industrial systems.

In testing of recirculating water samples, a substrate evaluation was employed. In such testing, identical portions of-water samples are treated with varying concenpared by merely combining the respective ingredients and mixing thoroughly at standard conditions may be fed continuously to the treated system, eg by means of a metered pump, or may be fedperiodically at intervals calculated to control the growth of slime-forming organisms in the system. Naturally, in the treatment of cooling water the feeding of the inventive compositions must be designed to compensate for blowdown in those systems which employ that expedient.

As would be expected, the inventive composition may be added to the cooling water or paper and pulp mill systems at any convenient point. Naturally, in once-through or non-circulating systems, the composition must be added upstream from the point or points at which microorganism control is desired. In circulating systems or pulp and paper systems, the compositions may be added at any point provided that the time lapse and the conditions experienced between point of addition and-the point at which the effect of the composition is experienced are not so drastic as to result in the neutralization of the-effect of the composition.

SLIME CONTROL EFFECTIVENESS The inventive methods and materials were tested with respect to their performance in the control of slime formation in industrial systems, In this test an industrial recirculating water was obtained from a system which was currently experiencing problems in respect to the formation of slime by microorganisms. Such tests do not demonstrate the efficiency of the biocide employed with respect to specific species of microorganisms but instead supply a practical demonstration of the efficacy of the biocide tested in relation to those communities of microorganisms which have evidenced the treatment of paper mill and cooling water, effective 5 trations of biocide and two portions are left untreated biocidal action is obtained when the concentration or to serve as controls. The control portions are plated for treatment level of the combination or admixture of biototal count at the beginning of biocide treatment and cides is between 0.5 parts per million to 1,000 parts per all portions are plated for total count at some suitable million, and preferably between 1 and parts per time period (5) after beginning biocide treatment. million, based upon the total content of the system 10 ing h ounts ain fr h pl g the p ,treated, such as the total quantity of cooling water or centage kill (based on the inital control count may be paper mill water. 7 calculated. In the following example, the water sample The compositions may also be utilized for the preserwas taken from a paper mill save-all unit located in the vation of slurried and emulsions containing carbohy- Southern P oflhe Ufllted Statesdrates, proteins, fats, oils, etc. Dosage levels for this 15 For the purposes of comparison a composition of P p range'lil the vlcmlty of 9 to this invention was evaluated with two recognized corn- The composiuons of the invention which can be premercial biocides.

Quantity of Percent Kill Biocidal Material Biocide (ppm) After 3 Hours (5%) N-2-nitrobutyl-morpholine 5 7 (5%) Pentachlorophenyl I0 27. 25 30 Inert 50 34 100 37 Pentachlorophenyl (10% Active) 5 0 10 0 25 0 50 0 I 100 3 Sodium dimethyldithiocarbamate (10% Active) 5 I8 10 29 25 M 50 43 too 47 "EFFICACY RELATIVE TO FUNGI In order to ascertain whether in fact-the inventive compositions were effective in controlling fungi, evaluations were made following the procdeure described by Sherma, et al., JOURNAL FOR THE TECHNICAL ASSOCIATION OF THE PULP AND PAPER INDUS- TRY," 36, 20A30A, I953. The described procedure generally entails incorporating the biocide under test in a nutrient substrate s uch as agar, malt, etc.,- and pouring the resulting medium in a Petri dish and allowing the medium to solidify. A button of fungus inoculum is placed on the surface of the solidified medium and the medium is incubated for a period of 14 days. After the period, the diameter of the colony is measured and compared with the diameter of the button of inoculum originally placed upon the surface. If there is no increase in the diameter, the growth of the fungus is considered to be completely inhibited and the treatment level which effectuates this is considered the inhibitory concentration.

The fungi species utilized as the test microorganism toevaluate the efficacy of the present compositions were Penicillium expansum and Aspergillus niger. The study revealed that the above 10% active composition of this'invention inhibited the growth of Penicillium expansum at a treatment level of 300 ppm and 300 ppm completely inhibited the growth of Aspergillus niger.

Bactericidal Effectiveness .The bactericidal effectiveness of a U1 mixture of the two components of this invention (l0% active) is demonstrated by the following data in which the inhibiting Biocide Materials Inhibition quantity (ppm) 1 N-Z-nitrobutyl morpholine (57) Pentachlorophenyl (5%) 1500 lnert (90% Accordingly. since the waters of pulp and paper mills and the water of cooling systems generally predominately contain bacteria such as Aerobacler aerogenes and some fungi such as Penicillium expansum and Aspergillus niger. it is apparent from the foregoing evaluations and studies that the inventive composition will effectuate the claimed objective of controlling microorganisms of aqueous systems.

It should be noted that while the preponderance of evidence has been derived from the treatment of samples taken from paper and pulp mill aqueous systems, the compositions and methods of the present invention are broadly applicable to the treatment of aesthetic waters as well as industrial waters such as cooling waters which are plagued by deposits formed by slime-forming organisms, or by the very presence of such organisms.

Having thus described the invention, what is claimed l. A composition for the control of the growth of the microorganism Aerobact er aerogenes in aqueous systerns comprising N-2-nitrobutyl morpholine and pentachlorophenol wherein the weight ratio of the morpholine to the phenol ranges from about 5:95 to about :5 respectively.

2. The composition of claim 1 where said'ratio is about 50:50.

3. A method for controlling the growth of the microorganism Aerobacter aerogenes in an aqueous system which comprises adding to said system an effective amount of a composition comprised of N-2-nitrobutyl morpholine and pentachlorophenol wherein the weight ratio of the morpholine to the phenol ranges from about 5:95 to about 95:5 respectively.-

4. The method of claim 3 where said ratio is about 5. The method of claim 3 wherein said composition is added to said system in an amount of from about 0.1 to about 1,000 parts per by weight of said composition per million parts by weight of said aqueous system.

6. The method of claim 5 where said composition amount is from about 1 to about parts per million of said aqueous system.

7. The method of claim 5 wherein the aqueous system is that'of a cooling water system.

8. The method of claim 5 wherein the aqueous system is that of a pulp and papermill system. 

1. A composition for the control of the growth of the microorganism Aerobacter Aerogenes in aqueous systems comprising N-2-nitrobutyl morpholine and pentachlorophenol wherein the weight ratio of the morpholine to the phenol ranges from about 5: 95 to about 95:5 respectively.
 2. The composition of claim 1 where said ratio is about 50:50.
 4. The method of claim 3 where said ratio is about 50:50.
 5. The method of claim 3 wherein said composition is added to said system in an amount of from about 0.1 to about 1,000 parts per by weight of said composition per million parts by weight of said aqueous system.
 6. The method of claim 5 where said composition amount is from about 1 to about 100 parts per million of said aqueous system.
 7. The method of claim 5 wherein the aqueous system is that of a cooling water system.
 8. The method of claim 5 wherein the aqueous system is that of a pulp and papermill system. 